2,562 research outputs found
Silver(I) and mercury(II) complexes of meta- and para-xylyl linked bis(imidazol-2-ylidenes)
Mononuclear silver and mercury complexes bearing bis-N-heterocyclic carbene (NHC) ligands withlinear coordination modes have been prepared and structurally characterised. The complexes form metallocyclic structures that display rigid solution behaviour. A larger metallocycle of the form [L2Ag2]2+ [where L = parabis(N-methylimidazolylidene)xylylene] has been isolated from the reaction of para-xylylene-bis(N-methylimidazolium) chloride and Ag2O. Reaction of silver- and mercury-NHC complexes with Pd(NCCH3)2Cl2 affords palladium-NHC complexes via NHC-transfer reactions, the mercury case being only the second example of a NHC-transfer reaction using a mercury-NHC complex
Acute anti-allodynic action of gabapentin in dorsal horn and primary somatosensory cortex: Correlation of behavioural and physiological data
Neuropathic pain is a debilitating consequence of neuronal injury or disease. Although first line treatments
include the alpha-2-delta (a2d)-ligands, pregabalin and gabapentin (GBP), the mechanism of their
anti-allodynic action is poorly understood. One specific paradox is that GBP relieves signs of neuropathic
pain in animal models within 30min of an intraperitoneal (IP) injection yet its actions in vitro on spinal
dorsal horn or primary afferent neurons take hours to develop. We found, using confocal Ca2þ imaging,
that substantia gelatinosa neurons obtained ex vivo from rats subjected to sciatic chronic constriction
injury (CCI) were more excitable than controls. We confirmed that GBP (100 mg/kg) attenuated mechanical
allodynia in animals subject to CCI within 30min of IP injection.Substantia gelatinosa neurons
obtained ex vivo from these animals no longer displayed CCI-induced increased excitability.
Electrophysiological analysis of substantia gelatinosa neurons ex vivo suggest that rapidly developing
in vivo anti-allodynic effects of GBP i) are mediated intracellularly, ii) involve actions on the neurotransmitter
release machinery and iii) depend on decreased excitatory synaptic drive to excitatory
neurons without major actions on inhibitory neurons or on intrinsic neuronal excitability. Experiments
using in vivo Ca2þ imaging showed that 100 mg/kg GBP also suppressed the response of the S1 somatosensory
cortex of CCI rats, but not that of control rats, to vibrotactile stimulation.
Since the level of a2d1 protein is increased in primary afferent fibres after sciatic CCI, we suggest this
dictates the rate of GBP action; rapidly developing actions can only be seen when a2d1 levels are
elevated
Relationship of literacy and heart failure in adults with diabetes
<p>Abstract</p> <p>Background</p> <p>Although reading ability may impact educational strategies and management of heart failure (HF), the prevalence of limited literacy in patients with HF is unknown.</p> <p>Methods</p> <p>Subjects were drawn from the Vermont Diabetes Information System Field Survey, a cross-sectional study of adults with diabetes in primary care. Participants' self-reported characteristics were subjected to logistic regression to estimate the association of heart failure and literacy while controlling for social and economic factors. The Short Test of Functional Health Literacy was used to measure literacy.</p> <p>Results</p> <p>Of 172 subjects with HF and diabetes, 27% had limited literacy compared to 15% of 826 subjects without HF (OR 2.05; 95% CI 1.39, 3.02; <it>P </it>< 0.001). Adjusting for age, sex, race, income, marital status and health insurance, HF continued to be significantly associated with limited literacy (OR 1.55, 95% CI 1.00, 2.41, <it>P </it>= .05).</p> <p>After adjusting for education, however, HF was no longer independently associated with literacy (OR 1.31; 95% CI 0.82 – 2.08; <it>P </it>= 0.26).</p> <p>Conclusion</p> <p>Over one quarter of diabetic adults with HF have limited literacy. Although this association is no longer statistically significant when adjusted for education, clinicians should be aware that many of their patients have important limitations in dealing with written materials.</p
Validation of Self-Reported Health Literacy Questions Among Diverse English and Spanish-Speaking Populations
BackgroundLimited health literacy (HL) contributes to poor health outcomes and disparities, and direct measurement is often time-intensive. Self-reported HL questions have not been validated among Spanish-speaking and diverse English-speaking populations.ObjectiveTo evaluate three self-reported questions: 1 "How confident are you filling out medical forms?"; 2 "How often do you have problems learning about your medical condition because of difficulty understanding written information?"; and 3 "How often do you have someone help you read hospital materials?" Answers were based on a 5-point Likert scale.DesignThis was a validation study nested within a trial of diabetes self-management support in the San Francisco Department of Public Health.ParticipantsEnglish and Spanish-speaking adults with type 2 diabetes receiving primary care.MethodsUsing the Test of Functional Health Literacy in Adults (s-TOFHLA) in English and Spanish as the reference, we classified HL as inadequate, marginal, or adequate. We calculated the C-index and test characteristics of the three questions and summative scale compared to the s-TOFHLA and assessed variations in performance by language, race/ethnicity, age, and education.Key resultsOf 296 participants, 48% were Spanish-speaking; 9% were White, non-Hispanic; 47% had inadequate HL and 12% had marginal HL. Overall, 57% reported being confident with forms "somewhat" or less. The "confident with forms" question performed best for detecting inadequate (C-index = 0.82, (0.77-0.87)) and inadequate plus marginal HL (C index = 0.81, (0.76-0.86); p<0.01 for differences from other questions), and performed comparably to the summative scale. The "confident with forms" question and scale also performed best across language, race/ethnicity, educational attainment, and age.ConclusionsA single self-reported HL question about confidence with forms and a summative scale of three questions discriminated between Spanish and English speakers with adequate HL and those with inadequate and/or inadequate plus marginal HL. The "confident with forms" question or the summative scale may be useful for estimating HL in clinical research involving Spanish-speaking and English-speaking, chronically-ill, diverse populations
Modelling hair follicle growth dynamics as an excitable medium
The hair follicle system represents a tractable model for the study of stem cell behaviour in regenerative adult epithelial tissue. However, although there are numerous spatial scales of observation (molecular, cellular, follicle and multi follicle), it is not yet clear what mechanisms underpin the follicle growth cycle. In this study we seek to address this problem by describing how the growth dynamics of a large population of follicles can be treated as a classical excitable medium. Defining caricature interactions at the molecular scale and treating a single follicle as a functional unit, a minimal model is proposed in which the follicle growth cycle is an emergent phenomenon. Expressions are derived, in terms of parameters representing molecular regulation, for the time spent in the different functional phases of the cycle, a formalism that allows the model to be directly compared with a previous cellular automaton model and experimental measurements made at the single follicle scale. A multi follicle model is constructed and numerical simulations are used to demonstrate excellent qualitative agreement with a range of experimental observations. Notably, the excitable medium equations exhibit a wider family of solutions than the previous work and we demonstrate how parameter changes representing altered molecular regulation can explain perturbed patterns in Wnt over-expression and BMP down-regulation mouse models. Further experimental scenarios that could be used to test the fundamental premise of the model are suggested. The key conclusion from our work is that positive and negative regulatory interactions between activators and inhibitors can give rise to a range of experimentally observed phenomena at the follicle and multi follicle spatial scales and, as such, could represent a core mechanism underlying hair follicle growth
The relationship between literacy and multimorbidity in a primary care setting
<p>Abstract</p> <p>Background</p> <p>Multimorbidity is now acknowledged as a research priority in primary care. The identification of risk factors and people most at risk is an important step in guiding prevention and intervention strategies. The aim of this study was to examine the relationship between literacy and multimorbidity while controlling for potential confounders.</p> <p>Methods</p> <p>Participants were adult patients attending the family medicine clinic of a regional health centre in Saguenay (Quebec), Canada. Literacy was measured with the Newest Vital Sign (NVS). Multimorbidity was measured with the Disease Burden Morbidity Assessment (DBMA) by self-report. Information on potential confounders (age, sex, education and family income) was also collected. The association between literacy (independent variable) and multimorbidity was examined in bivariate and multivariate analyses. Two operational definitions of multimorbidity were used successively as the dependent variable; confounding variables were introduced into the model as potential predictors.</p> <p>Results</p> <p>One hundred three patients (36 men) 19–83 years old were recruited; 41.8% had completed 12 years of school or less. Forty-seven percent of patients provided fewer than four correct answers on the NVS (possible low literacy) whereas 53% had four correct responses or more. Literacy and multimorbidity were associated in bivariate analyses (p < 0.01) but not in multivariate analyses, including age and family income.</p> <p>Conclusion</p> <p>This study suggests that there is no relationship between literacy and multimorbidity when controlling for age and family income.</p
Binocular summation and other forms of non-dominant eye contribution in individuals with strabismic amblyopia during habitual viewing
YesAdults with amblyopia ('lazy eye'), long-standing strabismus (ocular misalignment) or both typically do not experience visual symptoms because the signal from weaker eye is given less weight than the signal from its fellow. Here we examine the contribution of the weaker eye of individuals with strabismus and amblyopia with both eyes open and with the deviating eye in its anomalous motor position. The task consisted of a blue-on-yellow detection task along a horizontal line across the central 50 degrees of the visual field. We compare the results obtained in ten individuals with strabismic amblyopia with ten visual normals. At each field location in each participant, we examined how the sensitivity exhibited under binocular conditions compared with sensitivity from four predictions, (i) a model of binocular summation, (ii) the average of the monocular sensitivities, (iii) dominant-eye sensitivity or (iv) non-dominant-eye sensitivity. The proportion of field locations for which the binocular summation model provided the best description of binocular sensitivity was similar in normals (50.6%) and amblyopes (48.2%). Average monocular sensitivity matched binocular sensitivity in 14.1% of amblyopes' field locations compared to 8.8% of normals'. Dominant-eye sensitivity explained sensitivity at 27.1% of field locations in amblyopes but 21.2% in normals. Non-dominant-eye sensitivity explained sensitivity at 10.6% of field locations in amblyopes but 19.4% in normals. Binocular summation provided the best description of the sensitivity profile in 6/10 amblyopes compared to 7/10 of normals. In three amblyopes, dominant-eye sensitivity most closely reflected binocular sensitivity (compared to two normals) and in the remaining amblyope, binocular sensitivity approximated to an average of the monocular sensitivities. Our results suggest a strong positive contribution in habitual viewing from the non-dominant eye in strabismic amblyopes. This is consistent with evidence from other sources that binocular mechanisms are frequently intact in strabismic and amblyopic individuals
A Geometric Approach to CP Violation: Applications to the MCPMFV SUSY Model
We analyze the constraints imposed by experimental upper limits on electric
dipole moments (EDMs) within the Maximally CP- and Minimally Flavour-Violating
(MCPMFV) version of the MSSM. Since the MCPMFV scenario has 6 non-standard
CP-violating phases, in addition to the CP-odd QCD vacuum phase \theta_QCD,
cancellations may occur among the CP-violating contributions to the three
measured EDMs, those of the Thallium, neutron and Mercury, leaving open the
possibility of relatively large values of the other CP-violating observables.
We develop a novel geometric method that uses the small-phase approximation as
a starting point, takes the existing EDM constraints into account, and enables
us to find maximal values of other CP-violating observables, such as the EDMs
of the Deuteron and muon, the CP-violating asymmetry in b --> s \gamma decay,
and the B_s mixing phase. We apply this geometric method to provide upper
limits on these observables within specific benchmark supersymmetric scenarios,
including extensions that allow for a non-zero \theta_QCD.Comment: 34 pages, 16 eps figures, to appear in JHE
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